1. Field of the Invention
The present invention relates to a device for fastening a panel of semi-rigid material, such as a so-called acoustic panel having a decorative face, to a substrate such as a wall or ceiling. The term xe2x80x9csemi-rigidxe2x80x9d is used for materials such as fiberglass (glass fiber reinforced resin), or other fibrous material, used in buildings for heat or sound insulation. Such materials are structurally weak but are capable of receiving special fasteners designed to be used with such material. The panels with which the present invention is primarily concerned usually have a decorative face and it is desired that any fastener used should be a so-called xe2x80x9cblindxe2x80x9d fastener which is hidden and does not noticeably spoil the appearance of the face.
2. Prior Art
Many different fastening devices and methods have been used hitherto with acoustic panels or similar panels, in a manner which does not affect the appearance of the panel.
In some cases plain, unmodified panels have been attached to a wall by glue or resin spots, or have been impaled onto the spikes of special impaling clips or fasteners. The impaling-type fasteners often need the addition of glue to hold properly. The use of glue means that the panel cannot be removed or re-adjusted in position without practically destroying the panel.
The impaling spikes usually slope upwards, to better hold the panel. This has the drawback that the panel must move downwards during its installation, so that a gap or xe2x80x9crevealxe2x80x9d must occur between the top of a panel and a ceiling.
In other devices, a fastener part is attached to the rear of a panel, and mated with another fastener part attached to the wall. The fastening devices may involve metal clips such as so-called Z-clips, magnets, xe2x80x9cVelcroxe2x80x9d type fasteners, or concealed splines and tracks. These require time in the factory to attach the fastener portion to the panel, and care must be taken to properly align the wall portion of the fasteners with the panel part; for these reasons I prefer to avoid any component which needs prior attachment to the panels. The Z-clips need a downwards motion during installation and therefore also give a reveal. Some such fasteners, such as the xe2x80x9cVelcroxe2x80x9d type, do not hold strongly enough to be used on large panels or to hold panels to ceilings.
Although the semi-rigid material of these panels is too weak to hold ordinary wood screws, some special screws or fasteners have been designed for fiberglass insulation, for example as shown in the following U.S. patents:
No. 4,762,453, issued Aug. 9, 1988 to DeCaro,
No. 4,917,554, issued Apr. 17, 1990 to Bronn, and
No. 5,426,905, issued Jun. 27, 1995 to Rollhauser et al.
The screws or fasteners shown in these patents have large heads and are therefore unsuitable for use where a hidden or unobtrusive fastener is needed.
U.S. Pat. No. 4,846,622, issued Jul. 11, 1989 to Lien, describes a securing device for a hollow plastic frame part such as a window frame. The device includes a screw part which is rotatably attached to a substrate by an anchor screw, and which can be rotated to engage with an internally threaded holding element attached to the frame, rotation of the screw part being effected by a non-circular rod inserted through a bore in the outer face of the frame. This would not be a suitable construction for my purposes, firstly since it requires that the holding element be attached to the frame by a small screw before installation. Quite apart from the fact this kind of screw could not be used with semi-rigid material, as indicated above it is desired in the present invention to avoid use of any parts which need prior attachment to the acoustic panels. Also, Lien does not show a hidden fastener; he has a bore in the outer face of his frame which is quite noticeable, and which in accordance with his construction must be larger than the head of his anchor screw to accommodate the non-circular rod. In fact, this bore shown by Lien is almost twice the diameter of his anchor screw.
The present invention resulted from a need for an improved fastener, especially for acoustic or insulating panels made of semi-rigid material, the fastener having at least some of the following advantages over current fasteners:
1. It provides a strong hold on the panel so as to be suitable for holding ceiling panels;
2. It does not require the addition of any part by the panel manufacturer; it can be used on plain acoustic panels produced by many different manufacturers;
3. It is simple and quick to apply;
4. It provides a fastener which is almost entirely hidden, with only minimal disturbance of the front of the panel; and
5. It allows a panel to be removed and replaced.
The present invention, as with that of my aforesaid ""130 application, provides a fastener for attaching a rear face of a panel of semi-rigid material to a substrate, in which the fastener comprises:
an anchor part for attachment to the substrate surface;
a screw part having an inner end connected to the anchor part so as to be rotatable relative to the substrate, the screw part having a helical member with an outer end capable of penetrating the rear face of the panel upon rotation of the screw part;
drive means for rotating the screw part including an elongated drive rod arranged to engage an outer end portion of the screw part.
The drive rod is capable of extending through the panel when the helical member contacts the rear face of the panel so that the drive rod is accessible at the front face of the panel to cause the helical member to rotate and penetrate the rear face of the panel and to become embedded in an inner portion of the panel to secure the panel onto the substrate. The drive rod is removable after the panel has been secured, and this drive rod is a small fraction of the diameter of the screw part so as to require only a small hole in the panel, and so that the fastener is essentially concealed within the panel.
It will be understood that the screw part used in accordance with this invention is fundamentally different from screw devices hitherto known to me. It has a large diameter helical member or flange, similar to that of an auger, the helical member or flange being preferably well over an inch in diameter. Unlike the kind of screw part shown by Lien, it can penetrate the rear face of a panel without any prior preparation of the panel, and for example it can penetrate and engage an unapertured panel. It is also unlike all screws known to me, except that of Lien, in being driven, not from its head, but from the other or xe2x80x9ctailxe2x80x9d end, i.e. the end that first penetrates the semi-rigid material. This is achieved by use of the drive rod which projects from the outer end of the screw part and passes through the panel material and is accessed from the front face of the panel.
The drive rod may be a non-circular rod or pin, for example a hexagonal rod, which engages in a non-circular recess in the outer end of the screw part, and which can be pulled out of the recess when the panel has been installed. Alternatively, the drive rod may be formed integrally with the screw part, for example being formed of plastic, and may be broken off when the panel has been installed. It may have a pointed outer end for penetrating the panel.
Preferably, the screw part includes a shaft rotatably held by the anchor part, and a helical member surrounding the shaft. The helical member has a diameter greater than the length of the screw part; in fact the diameter of the helical member is usually more than twice the shaft length. The drive rod has a diameter such that the bore formed in the panel is not noticeable when the drive rod is withdrawn. The drive rod has a diameter which is a small fraction (say less than xc2xc) the screw part diameter, being preferably less than xe2x85x9 of an inch, and less than xe2x85x9 the maximum diameter of the helical member, and most preferably less than {fraction (1/16)} of this maximum diameter. These diameters of course also apply to the non-circular recess which receives the drive rod.
The term xe2x80x9chelical memberxe2x80x9d covers not only an auger-type flight but may include a helical rod surrounding a shaft, and having an inner end connected to the shaft and a pointed outer end, operating somewhat in the manner of a corkscrew.
The anchor part may be a plate having at least one hole for screw attachment of the plate to the substrate. The plate may be firmly secured to the substrate, and preferably has at least one lug extending perpendicularly therefrom and capable of penetrating the rear face of the panel to stabilize the position of the panel.
Alternatively, the anchor part may be simply a wood-type screw or fastener fixed to the substrate and which rotatably receives an inner end portion of the screw part, this portion being rotatably held by the head of the anchor screw. This inner end portion may be a base member attachable to an outer or complementary member. Here, the base member has a bore for receiving the anchor screw and is attachable to the substrate while the base member is detached from the outer or complementary member. This construction allows the outer or complementary member to be attached to the base member after the latter has been attached to the substrate by the anchor screw, and this in turn means that the anchor screw may be co-axial with the drive rod, allowing for accurate positioning of the panel, as will be described fully below. It also means that the recess in the outer or complementary member which receives the drive rod may be of smaller diameter than the head of the anchor screw, unlike the situation in Lien referred to above.
One method of using the device, as described in my previously filed ""130 application as aforesaid, involves firstly attaching anchoring means to the substrate so as to rotatably hold the screw part, and then inserting the drive rod into the non-circular recess in the outer end of the screw part. The panel is then pushed onto the drive rod which has a sharpened outer end so that it penetrates the panel and emerges from the front of the panel, where it is rotated by a tool to turn the screw part and draw this into the rear of the panel until the panel is secure.
While this procedure works, it has the drawback that precise positioning of the panel may be difficult. The drive rod needs to be inserted into the rear of the panel while this is still separated from the substrate by at least the length of the screw member and the drive rod, so that care and judgement is required if the panel is to be correctly positioned in its final location.
In accordance with another aspect of the present invention, an improved procedure is provided whereby a panel can be more precisely positioned than using the method described in my aforesaid ""130 application. The present invention also provides a modified fastener device particularly suited to the new method. The new method can however also be used with certain of the fastener devices described in my aforesaid ""130 application.
The improved procedure makes use of a fastener in which the screw part is rotatably attached to the substrate by an anchor screw which is co-axial with the non-circular drive recess in the outer end of the screw part and therefore also co-axial with the drive rod, and, generally, co-axial with the screw part. This allows the location of the anchor screw to be aligned with a bore in the panel which is preformed before the drive rod is put in place, rather than being formed by the drive rod upon being pushed through from the panel rear face, as in my aforesaid ""130 application.
Constructions of the fastener device in which an anchor screw is co-axial with the screw part and its drive means were shown in my aforesaid ""130 application. The present application shows a further, preferred design for co-axial anchor screw and drive rod having additional desirable features. In all these designs, in order to allow insertion of the anchor screw, the screw part is separable into a base member and an outer or complementary member, the base member being attached to the substrate by the anchor screw while separated from the outer or complementary member.
The fastener device in accordance with this aspect of the invention may be defined as comprising:
a screw part having an inner end capable of being rotatably held relative to the substrate by an anchor screw having a head, the screw part having a helical member with an outer end capable of penetrating the rear face of the panel upon rotation of the helical member;
drive means for rotating said screw part, the drive means including a non-circular drive recess accessible from an outer end of the screw part and suitable for engagement by a drive rod which is capable of extending fully through a transverse bore in the panel so that the drive rod is accessible for rotation at the front face of the panel to cause the helical member to penetrate and engage a rear portion of the panel, and which rod is removable from the screw part after the panel has been secured so that the fastener is essentially concealed within the panel;
the screw part including a base member and a complementary member, the base member having an aperture for receiving the anchor screw and being attachable to the substrate by the head of the anchor screw while the base member is separate from the complementary member, the complementary member being attachable to the base member when the anchor screw is in place in the base member aperture, said complementary member providing the non-circular drive recess for the drive rod, the base member being rotatable about the axis of the anchor screw when the anchor screw is in place in the substrate;
and wherein the axis of the base member aperture which receives the anchor screw is coincident with the axis of the non-circular drive recess for the drive rod in the complementary member when the two members are assembled together, whereby the bore in the panel which receives the drive rod may be co-axial with the anchor screw.
The base member may include the helical member and the aperture for receiving the anchor screw, and may have a central socket leading to the aperture for the anchor screw. The complementary member may be an insert engageable in the central socket and which has the non-circular recess for receiving the drive rod. This is the preferred arrangement of this present invention. The central socket is non-circular, and the insert has an outer surface which fits non-rotatably into the central socket. In the preferred embodiment in accordance with this present invention, the insert is connected to the base member by a flexible hinge part which allows the insert to be removed from the base member while the anchor screw is being inserted into the base member aperture.
In alternative arrangements, the complementary member includes the helical flight and has screw threaded attachment to the base member.
The invention also provides a method for attaching the rear of a panel of semi-rigid material to a substrate at a desired installation position by making use of a screw part having an inner end capable of being held relative to the substrate by an anchor screw having a head, such that the screw part can rotate relative to the substrate about an axis coaxial with the anchor screw, the screw part having a helical member with an outer end capable of penetrating the rear of the panel upon rotation of the helical member, the screw part comprising a base member and a complementary member, the base member having an aperture for the anchor screw and the complementary member having a non-circular drive recess for a drive rod which is co-axial with the anchor screw aperture when the two members are assembled together, the method comprising the steps of:
forming a transverse bore in the panel and marking an anchor screw location for the anchor screw in the substrate such that the anchor screw will be aligned with the transverse bore when the panel is in its desired installation position;
fixing the base member of the screw part to the substrate by means of the anchor screw inserted at the said location, with the anchor screw having a head engaging inside the aperture of the base member, whereby an inner end of said base member is rotatably held relative to the substrate by the anchor screw head;
fitting the complementary member of the screw part to the base member;
placing a panel at the installation position and passing an elongated drive rod through the said transverse bore in the panel and fitting an inner end of the drive rod into the non-circular drive recess of the complementary member so that a portion of the drive rod extends through the panel and has its outer end part protruding from a front face of the panel when the helical member of the screw part contacts the panel rear face,
rotating the drive rod by its protruding end part to cause the helical member of the screw part to penetrate and engage a rear portion of the panel, and, upon further rotation of the screw part, to secure the panel onto the substrate,
and removing the drive rod from the outer end of the screw part after the panel has been secured so that the fastener is essentially concealed within the panel.
Marking the locations for the anchor screw hole and making the transverse bores in the panel may be done simultaneously by holding the panel in a position in which it is to be installed while forming each bore in the panel by use of a penetrating tool inserted from the front face, which tool at the same time also marks an anchor screw location in the substrate, so that the anchor screw locations are aligned with the bores.
Alternatively, the making of the bores in the panel and the marking of locations for the anchor screws may be done separately by using a template, or other measuring means, to ensure that the anchor screws are located correctly relative to the bore positions for the panel to be properly positioned.
The drive rod may be a non-circular rod or pin, for example a hexagonal rod, which engages the non-circular drive recess in the screw part, and which can be pulled out of the recess when the panel has been installed. With this method it is possible to use a standard Allen key or wrench as the drive rod, since its outer end does not need to pass through the panel. Also, the two-member screw part allows the use of a drive rod which is much smaller in diameter than the head of the anchor screw, unlike in Lien.